tbone heller

Honda V-6 swap? Honda sux! This is a V-8 forum. Well, there goes the neighborhood. LMAO!!

MRM331

LOL.

That's how I felt when we first started letting these GM people move in on the V8 scene 7 or 8 years ago. All in all they seem to have turned out to be pretty decent people though, right?

So I started pricing this out yesterday:

Swap kit: $4000
AEM/MS3 ecu and wideband O2 sensor: $1500
J32a2 engine and harness: $600 - $900, we'll say $750

Since the kit uses the Miata radiator, trans, rear and even exhaust that's about it. I could be rolling with this for $6300 over the cost of the car itself.

That said, since this does use stock Miata drive line components upgrading to the best available would be awesome. To that end I'd likely add from Planet Miata:

Used Miata 6-speed: $700
Used Miata 7" 3.9 limited slip rear upgrade package: $1300

I think that could make a pretty potent package for $8300.

After passing the Laguna on to a new owner I plan to pick up a well cared for white 1991 I know of, upgrade the suspention, bolt on my track equipment (seats/tires/wheels/brake pads) and track it for a summer with its 1.6 while collecting parts for its power train upgrades. I figure a year with only 90 or so hp can only help me develop my line and braking better. The car already has upgraded brakes, sway bars, radiator and a roll bar so suspention and a hardtop and I'll be ready to go.

If I go this route I can get it into Lotus territory for under $9k and have a fun little package to flog at the track for a few years until I feel the need to again "have another". Since this swap seems to able to be done without any modifications to the body of the car I'd be able to at that point sell it as is, pull out the j engine and drivetrain and re 1.6 it to sell it or even pull the j drivetrain to sell and use the '91 as the donor for the next build...

The only concern I still have is the ability of this engine to be flogged at a road course. It seems pretty stout from what I have been reading but I also have not found any one who is actually beating on one like I will be. That said, the replacement cost of the engine is not as bad as I thought it would be. I'm seeing good donor packages (engine/harness/ecu/trans-sell ecu and fwd transaxle) for $600 to $1000. This even makes the rebuild kit not that bad at $600. A good used donor with a fresh rebuild would only run me around $1400 or so which is less than I have in just the rotating assembly of the Laguna.

The coolest part: "Mazda" + "Honda" = "Monza"

How cool is that?

-Jason

577nitro

Jason,
you don't have to buy the AEM $1400 box, just look at RPM systems (Don) up in NYweb site or video. They can convert your ECU and harness for under 750. It will have to be a matching set, preferably a 99-01 J32a from Acura TL/CL etc. also the SuperfastMiata guys will sell a partial kit as you can make your own sub-frame. Also the flywheel is from an Acura Integra and the disc is a Miata ...This should help you out...I've been looking over and talking to a lot of the guys doing the conversions.

MRM331

So they do what I do...interesting.

Honestly I think I'll probably look into making up my own MS3 harness for this. I've been doing some reading up on the MegaSquirt boards and I think its very doable. This would also give me then another area I can start churning out parts for on my site.

Does anyone know is VVT an on/off type of thing or is it progressive? If it just actuates at a certain rpm/load point running it via a MS will be a breeze. If it's progressive it could be a deal breaker. Beyond that little issue all I need to figure out is how many teeth the crank and cam sensor have on the particular J engine I'll use and the coil type.

I'm getting excited about this. Someone buy my Laguna!

-Jason

577nitro

forums like j32a.com all have a wealth of information on things like VVT and which years have them, and how to get them to work..when I get home, i'll provide them to you...doing your own wiring would benefit many and will my prediction be the future for these swaps...The V6 in all of its forms (i.e ne Ford GT) will be eqaul to the number of v8s same as the LFX chevy. The Honda just are very sweet little reliable engines with thousands of racing hours in their veins...You will find that you may still not need a MS system if you can do the cracking of the ECU.

MRM331

Thanks Fred,
I just checked out j32a.com and a few video links there of a civic with this engine passing some serious competition at a track day:


Apparently the engine can handle track day flogging just fine. I'm really leaning this direction now as my next project.

Funny, if you watch the video above the guy has the same problem I run into at the track: people in high end cars unwilling to just swallow their pride and move over to let the "unworthy" car that has been filling up their mirrors for the last three laps to pass.

-Jason

577nitro

Yes, there are some very fast V6 miatas cars racing that do not bother to post on Miata sites. To my point about the 427 cobras, if a car can be raced with higher confidence from the driver, that driver will naturally go faster. If you are only going to drive them in a strait line ok, but not a real road course. Both the newer Ford 2011++ and the chevy are great alternatives. anyone who can build of the the V8s will enjoy them possibly more so, and there will be many of those engines at near give away prices for a long time.

DanielDD

Someone please do this swap and document it. I have read of maybe one other swap on Miata.net. Very interested in this as I am sure others are as well.

577nitro

Well according to a previous above post. SupererfastMiata has sold some 30 kits, but they just don't have out on this forum, or none at all. do some searching and you will find them as I have, some newer Ford and Chevy builds are underway. We will see them, and I remember back many years reading about the "monster Miata" and there was long period before it really caught on as well. I am stopped right now until I relocate back to Colorado

MRM331

The more I look into this the cooler it looks. I'm 99% sure I'm going this route for my next one at this point. The buzz around this engine reminds me of the way it was with the Ford V8's 15 years ago.

Here's where my thoughts are at this point:
Engine:
It looks like the best pull out engine for this that could be just "dropped in" would be a 2001-2003 Acura CL or TL J32a2. The engine in stock trim makes 260hp/232 foot pounds of torque, which is not too shabby compared to a stock 5.0's 225 hp. Using the engine with the stock intake requires ether turning the intake around and modifying the throttle body mount point to nose it down or having the kit company modify it so it sucks it's air in the side as opposed to the front. The side option looks cool but really started to concern me when I looked at the internal construction of the intake. The intake will work reversed on an NB with just a slight amount of help (not cutting and welding). I did a little poking around and found that the intake off an AWD 2009 Acura TL with a J37 is significantly shorter and lower than all other J intakes and can be purchased new from Honda for under $300. As a bonus it also just happens to be the best flowing and lightest of all J intake manifolds. I'm thinking that the combination of that intake and spacing down the front subframe like we do with Ford builds may just get me the ability to use an unmodified J37 intake and a Corvette aftermarket snorkel (like FM uses on their builds).
In addition to using the J37 intake I can also use the crank, rods and pistons from a J37a1 from a 2007-2013 Acura MDX to make myself a forged OEM "stoker Kit" that would up the displacement from 3.2 liters to 3.7. In the MDX the J37a1 made 300 hp/275 torque which I should be able to duplicate by fitting my J32a2 block with above parts (The J37 block has a different bolt pattern). The MDX parts I would need will run me about $1400 which is typical for a forged rotating assembly. I also found that an additional bump in power could be had by taking the J32a2 cams and installing them in a set of J35a3 heads from a 2001-02 MDX or 2004-2007 Saturn Vue. All told $3000 or so can build a very nice hybrid J engine that can make 300+ hp and get 30+ mpg.

Transmission/differential:
I made up a spreadsheet a year ago when I was looking at different ratios and trans options for the Ford 7.5 in my Laguna. I used it again for this and found that, much to my surprise, the last transmission I'd want is the Miata 6 speed. Where the 6 speeds we see in the V8 world have their "extra" gear inserted between a 1:1 4th gear and a normal overdrive 6th gear Mazda put thiers between 3rd and 4th. Fifth gear is 1:1 which is very odd IMHO. The sixth gear is actually lower than the fifth in a standard five speed. I'd actually do fine with a "normal" Miata five speed if it can hold up. Being that it actually started life in a truck I think I should be fine. If not they are cheap.
The best rear for all this would be the uber-rare 3.6 ring and pinion with limited slip. I have two options here: buy a new 3.6 ring and pinion set from Mazda for about $700 and have it installed in a 7" with existing limited slip or try to find an entire used 7" with the 3.6 in it Australia and have it shipped here. I still need to see which is cheaper. The first option will almost cost as much as the engine after having it set up properly, especially if I start with a 1.6 car.

ECU:
I really think if I had to do it today I'd go with the AEM standalone and a stock customized harness. I have three options here:

1. The above
2. The above with a "cracked" stock ECU
3. MS3 with a custom harness

Most take out engines come with a harness, ECU and transaxle for $1400 or so. The transaxles alone can be resold for $500 - $700 so I'm looking at $1000 here to be safe. Since I have the harness and stock ECU option 2 would be the cheapest depending on how much it costs to have them reprogrammed. If it's less than the $1300 for the AEM it may be worth it. The only downside is that options for tuning and datalogging are less with this option. The MS3 would offer the most opportunity to tune, datalog and such but unless few others are on the road before I do this myself I don't think I'll go this route at this point.

All in all this is really looking good.

-Jason

577nitro

Jason, you have found the same information that I saw plus, you want the "type-S" engine as most of the Japanese tuners say it has better insides (not confirmed by inspection) The intake is best left to the front, or you will get uneven flow and turbulence , flowing all intakes if possible will gain quite a lot (as with most stock engines). A couple of builders are trying dual TBs by opening up both runners. I would think one large unit would be just as beneficial. Also a guy in NY will convert your Miata harness, and do the ECU for less then $800 @ RPM SYSTEMS - ?? as for Don, he knows a great deal about these engines and various conversions

Gator Bait

The guy that is doing one locally just posted yesterday first start up. His will be one to replicate as everything he does is done with levels of OCD I can't even contemplate. (meant to be a compliment)

577nitro

Great, see if he is willing to post his contact..That would be helpful for others..personally, should I go this route, I may still use RPS as they have a lot of information and are the guys helping the superfast Miata folks. He also has the scoop on what flywheel/disc/clutch to use too..Also I would highly recommend adding a front brace across the engine to the original mount and not just using the adapter for complete support

Gator Bait

I thought I had...hmmm...anyway...it's here:

Titus's V6 Swap build thread

DanielDD

Here is the picture that bothers me. Both the starter and crankcase pan are below the subframe…

577nitro

Concur,,,but this guy has done some fabulous work ....it is his (Titus) own build site


V6 Miata | V6 Miata

MRM331

I've done a bit more research on the Engine management end of this project. By far the cheapest route is to just have a stock ecu modified to eliminate the anti-theft programming or get an ecu from an earlier car that did not have the lockout programming. Both of these options are tempting as stock computers are under $50 on eBay and most pullout engines come with a harness and an ecu. To have a stock ecu modified and then harness modified runs about $600. I don't want someone else modifying my harness for me. Maybe it's because I do this professionally myself but my standards when it comes to what a custom harness service gives you are pretty high. Even if I just had the ecu "cracked" I still would not have the ability to tune or modify the tune on the fly which is something I've really come to like to do. Data logging at the track would also be an issue.
The AEM option would give me a plug and play option that would be tunable. It's price is very high and to have the ability to add GPS data to its data logs I'd need to purchase another $300 unit. I'm also not so thrilled about how sort of sketchy the AEM site is about what you can and can not do with the series two ecu. I would also need to make sure the engine's sensors match the ones needed by this specific ecu which does not seem to made for manual transmission donor engines.
My original concern with using an MS3 was control of the VTEC feature of the engine. After looking into it this is not a concern at all. With an MS2 you just pick a rpm/load point to have it switch on using a spare output. The MS3x actually has a whole separate table I can use to iniate the feature and have it switch to a different ignition map when it does. Hooking it up is as simple as running two extra wires to a relay.
With that no longer a concern the MS3x is the best logical option for me that will allow me the level of tunability and datalogging that I need while still coming in under $700. I'd be running a wideband with any of the above so the $300 or so that will run is not really a deciding factor. Another advantage of running the MS3x is that it will give me the chance to build a standalone harness for it that I can market. I thought that adapting a stock CL harness would give me this but as that's already being done I think a stand alone MS3x harness could have more marketing potential, especially since such a harness could theoretically be used by anyone looking to mount a MS controlled J engine in anything.

One interesting thing that I ran into that I totally didn't expect was finding that the go-to large diameter throttle body for these engines is not a Honda one at all but aftermarket FORD MUSTANG THROTTLE BODIES! That's like circle of life, kuma matata Lion King stuff...

-Jason

577nitro

Jason, Great! with the MS you can also address the other J series engines which no one is offering (yet), but someone will have to address the starter and oil pan clearance issue, or run 32 inch tires.

MRM331

I'm thinking some type of skid plate would be in order. As far as the mounting system goes I'm not overly worried. The engine is very short compaired to even a Miata engine and fairly light. I think its only attached to the transaxle its usually fitted to using the bell housing bolts.

I'm actually more concerned about hood clearance. It seems like the thing to do in the Honda community is to just leave the hood off and run one of those funky no filter things that look like one big velocity stack. I'm not doing that. It's all going to fit under a stock or lightly modified hood. The main issue seems to be the throttle when the intake is turned around. I think I can bring three ideas from the Ford V8 Miata world to help with this. The first is the idea of having some material shaved from the mating surfaces of the upper and lower intake halves. Its possible there is no room to do this but I'll make sure of that before I give up on the idea. The other is spacing down the k frame. I currently have mine spaced down 3/8" which is about the limit for the factory studs. Since the mounting points are so far back compaired to other engines this may actually become closer to half inch at the front of the intake. Another idea I came up with is to use a throttle body elbow from a SN95 Mustang 5.0 in between the intake and the throttle body to angle it downward away from the hood. Since I'm planning on using a Mustang throttle anyhow this should be pretty easy to implement.

I really don't think the oil pan hangs down any lower than the modified Monster Miata one does.

-Jason

577nitro

That Mustang front intake should work well, or slightly trim and angle the inlet to where it look like the corvette sneaking air under the front hood edge. BTW, I spoke with the guy at SFMiata,and he told me they have been able to slightly relocate the starter and got it up almost an inch. Combine that with a better oil pan design (flattened out with baffles and all should be good to go. Also, there are a few guys out there using MS3 with motorcycle carbs like ITBs.....wild sounding

charchri4

I forgot about that titus thread but remember it from when I was doing fender research. Great car!

MRM331

If they can raise the starter up and raise the bottom of the oil pan that would be awesome. Other than those two spots the only thing I've seen that really concerns me is the picture Titus had of the Miata slave spaced out to clear the adapter plate and J block. It looks like the kit has two 1/2 inch spacers to do this which leaves the slave's pushrod coming out at a pretty bad angle. Originally Monster Miatas were set up this way as well which resulted in slave cylinders wearing out yearly (non-straight pushrod throws the aluminum piston off center in the iron bore and causes metal-on-metal contact which then makes the seals fail and leak). Looking at the picture there really seems to be no solution using the stock slave that would not involve extending the length of the clutch fork about an inch whch would then throw off the pedal to slave movement ratio. It's possible that the adapter and block could be modified to allow the slave to fit without the spacer. If that can't happen maybe it would be possible to replace the Miata slave with one that pulls instead of pushes. I know I've seen ones like that in the past. A puller slave could just be attached to the trans with a few brackets.

-Jason

MRM331

This picture:

MRM331

This picture:

577nitro

Puller would be a more simplistic approach, if there is room, or another look at a hydraulic throw-out bearing. I have seen several post which this has been done, but none conclusive with their posted results. I have had success with one on another build of mine


Speedway has this unit which may work well if there is room..price is right
http://www.speedwaymotors.com/Speedw...uery=910-25604